Lawn and garden tractors, riding lawn mowers, and the like are vehicles that carry a seated operator. These vehicles have a speed changing system controlled by the position of an accelerator for varying the ground speed of the vehicle. Typically, the accelerator comprises a foot pedal that is biased into a neutral position. To set the vehicle speed, the operator pushes down on the foot pedal until the pedal reaches a desired position and then holds the pedal with his foot against the spring force trying to return the pedal to neutral. The need to keep the pedal depressed can be tiring when the vehicle is being driven long distances at a constant speed, i.e. from one location to another or while mowing a large area of turf.
Accordingly, vehicles of this type have been equipped with various types of cruise control systems to allow the operator to maintain the vehicle speed at a set speed without having to manually keep the accelerator depressed. One such known cruise control system is a wholly mechanical system as disclosed in U.S. Pat. No. 4,620,575 to Cuba et al., which is assigned to the assignee of this invention. In this mechanical system, a pivotal cruise control lever can be set in a desired position to engage against a pin carried on the accelerator to prevent the accelerator from returning to neutral, thereby setting a cruise control speed as determined by the position of the cruise control lever. The cruise control lever can be maintained in different selected positions by engaging a tab on the lever with one of a plurality of serrations carried on the frame of the vehicle. The operator can temporarily speed up without losing the current cruise control setting since movement of the pin on the accelerator away from the cruise control lever is allowed. The cruise control lever simply forms an abutment which prevents the accelerator from returning all the way to neutral.
Electromagnetic cruise control systems are also known in vehicles of this type which use an electromagnet to lock the accelerator linkage in place to set a cruise control speed. However, such systems do not allow the operator to easily speed up from the cruise control speed. The operator can force the accelerator linkage further forwardly from the current cruise control setting if enough force is applied to the accelerator pedal, but this loses or destroys the current cruise control setting. If the cruise control is first disengaged before speed up is attempted, it is easier to manipulate the accelerator linkage, but the cruise control setting is again lost and must be subsequently reset. U.S. Pat. No. 5,168,970 to Hough et al. shows such an electromagnetic cruise control system. Unlike mechanical cruise control systems of the type shown in the Cuba patent referred to above, there are no known electromagnetic cruise control systems which permit a temporary speed up while retaining the current cruise control setting.